My Sienna from early on has had bad brakes. I take it in for service, they clean the brakes & turn the drum/rotors and in the next few thousands miles the knocking is back . The dealer told me I would need new drums/rotors costing $300+ dollars. I replaced them and we are still knocking & vibrating away. I have had my brakes worked on 5 times in 95,000 miles. My other cars don't require this amount of brake service.